The subject tables employ the same range of 13 performance indicators used in the overall World University Rankings 2018, brought together with scores provided under five categories. However, the overall methodology is carefully recalibrated for each subject, with the weightings changed to suit the individual fields.

CitationsOur research influence indicator looks at universities’ role in spreading new knowledge and ideas.

We examine research influence by capturing the number of times a university’s published work is cited by scholars globally. This year, our bibliometric data supplier Elsevier examined almost 62 million citations to more than 12.4 million journal articles, article reviews, conference proceedings and books and book chapters published over five years. The data include the 23,000 academic journals indexed by Elsevier’s Scopus database and all indexed publications between 2012 and 2016. Citations to these publications made in the six years from 2012 to 2017 are also collected.

The citations help to show us how much each university is contributing to the sum of human knowledge: they tell us whose research has stood out, has been picked up and built on by other scholars and, most importantly, has been shared around the global scholarly community to expand the boundaries of our understanding, irrespective of discipline.

The data are normalised to reflect variations in citation volume between different subject areas. This means that institutions with high levels of research activity in subjects with traditionally high citation counts do not gain an unfair advantage.

We have blended equal measures of a country-adjusted and non-country-adjusted raw measure of citations scores